add better generate

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

vendor/github.com/docker/cli/scripts/test/unit-with-coverage

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+set -eu -o pipefail
+
+# install test dependencies once before running tests for each package. This
+# reduces the runtime from 200s down to 23s
+go test -i "$@"
+
+for pkg in "$@"; do
+    ./scripts/test/unit \
+        -cover \
+        -coverprofile=profile.out \
+        -covermode=atomic \
+        "${pkg}"
+
+    if test -f profile.out; then
+        cat profile.out >> coverage.txt
+        rm profile.out
+    fi
+done